After their inclusion, all patients will undergo baseline myocardial perfusion study. Afterwards, patients will be randomized to two groups: a treated group and a cross group. Patients in the treated group will undergo HBOT treatment for 2 months and after that will repeat the same-protocol myocardial perfusion study and questionnaire, before entering a 2 month control period. Patients in the cross group will be evaluated at baseline, after a 2 month control period of no treatment and after 2 month period of HBOT treatment (after the cross to HBOT).